Preparation of three-dimensional ordered macro-/mesoporous SnO2 nanomaterials for electrocatalytic CO2 reduction

Herein, three-dimensional ordered macro-/mesoporous (3DOM/m) SnO 2 catalysts are synthesized at different calcination temperatures. The optimized catalyst 3DOM/m SnO 2 -450 shows excellent electrocatalytic performance in CO 2 -saturated 0.5 M KHCO 3 electrolyte with a current density of -25.5 mA cm -2 at -1.2 V (vs. RHE) and the maximum Faradaic efficiency of formate of 83% at -1.0 V (vs. RHE). The ordered interconnected macro-/mesoporous structure of the 3DOM/m SnO 2 promotes the mass/charge transfer across the electrode, and the mesoporous structure enables the catalyst to have more accessible reactive active sites, thus improving the catalytic selectivity and activity. This work not only offers an efficient porous tin-based catalyst for formate generation, but also provides a promising strategy for the design and fabrication of robust electrocatalysts for the electrocatalytic CO 2 reduction in the future. Data will be made available upon request. The three-dimensional ordered macro-/mesoporous SnO 2 nanomaterial shows a wide operating voltage range with the Faradaic efficiencies of over 70% for formate at -0.8 ~ -1.2 V (vs. RHE) in 0.5 M KHCO 3 solution for the CO 2 reduction reaction. • 3D ordered macro-/mesoporous SnO 2 materials are prepared by dual-templating method. • The optimized catalyst shows superior electrocatalytic CO 2 reduction performance. • The formate Faradaic efficiency can be maintained at 82% for a long time. • The unique macro-/mesoporous structure contributes to the high performance.